Guadalquivir is one of the major rivers of Spain. It begins at Sierra de Cazorla, passes through Córdoba and Seville and ends in Sanlucar de Barrameda (Atlantic Ocean).
Some Baetis species are often the first major hatches in the Spring and the last in the Fall, and on especially stable spring creeks they may emerge throughout the Winter.
Baetis nymphs are found in almost every trout stream, but they produce more broods and thicker hatches in cold, unpolluted, alkaline (Alkaline: Having a pH higher than 7 (opposite of acidic).